Elevators such as contemplated herein are not the commonly referred to elevators found in high-rise buildings used to rapidly transport passengers up and down between floors. The present elevator is a conveniance elevator, used primarily to carry goods up and down between two, three or perhaps four floors. For example, a residence built into the side of a hill may have a fireplace and kitchen on a level two stories above the garage. The home owner will have to carry fireplace wood and groceries to upper level. Due to health, age or simply a desire for convenience, the owner may have a convenience elevator built into his home to carry these items up and down the floors.
An elevator having specific use for transporting articles such as described above, is sometimes referred to in the industry as a dumbwaiter. These elevators generally have a load capacity rating in the range of 4-500 lbs. The current convenience elevator additionally contemplates the larger residential elevators having a load capacity rating in the range of 700 lbs. which can be used to transport a single person up and down several floors e.g. a person confined to a wheel chair.
Heretofor convenience elevators were generally comprised of a shaft or opening extending between floors, a carriage that fits the lateral dimensions of the shaft and designed to travel up and down in the shaft, and a power unit at the top or bottom of the shaft having a cable connected to the carriage to lift and lower the carriage. Because these elevators are primarily for convenience, the cost of installation is a major concern. The home owner simply cannot justify the convenience of the elevator if the cost of installation is many thousands of dollars. Thus many of the technical advances developed for passenger elevators are not applicable to convenience elevators.
In an effort to contain the cost of convenience elevators, a number of design features have been adopted resulting in undesirable characteristics heretofor considered inherent in convenience elevator design. A number of characteristics are described below:
The mounting for the convenience elevator is generally achieved by providing a load bearing beam over the top of the shaft. In that the usual home is not designed to provide these load bearing beams, it is often necessary to reconstruct a major segment of the ceiling structure. Unless done properly at a substantial cost to the home owner, the strength of the ceiling structure may be compromised.
The support for prior convenience elevators have been largely unitized and generally require installation prior to closing in the roof and ceiling. Installation for such structures after construction of the home is completed is a costly operation.
The lateral shaft dimensions for a convenience elevator is often very small and very difficult for even a single person to work in. Thus substantial pre-assembly is generally considered a necessity.
Isolation of vibration from the elevator's moving component is difficult to achieve at budget level cost and noise is a problem. Many home owners are reluctant to accept the noise levels that must be tolerated for low cost convenience elevators.
Many of the design characteristics available for passenger elevators for improved operation, repair and maintenance is too costly to install in convenience elevators. However, the failure to provide these features renders convenience elevators very costly to maintain.